Page 210 - International safety guide for oil tankers and terminals

INTERNATIONAL SAFETY GUIDE FOR OIL TANKERS AND TERMINALS

significant because the ship and terminal are connected by a
common stream of vapours, thereby introducing into the operation
---ใช้เพื่อการศึกษาเท่านั้น---
a number of additional hazards which have to be effectively
controlled.

11.1.13.3สมุด ศูนย์ฝกพาณิชย์นาวี
Detailed guidance on technical issues associated with vapour
emission control and treatment systems is available from a
number of sources. IMO has developed international standards
for the design, construction and operation of vapour collection
systems on tankers and vapour emission control systems at
terminals, and OCIMF has initiated and issued guidance on
vapour manifold arrangements (see Bibliography).

It should be noted that Vapour Emission Control Systems (VECS)
can serve tankers fitted with inert gas systems and also
non-inerted tankers.

A summary of the terminal’s VECS should be included in the
terminal information booklet.

11.1.13.2 Misconnection of Liquid and Vapour Lines

To guard against the possible misconnection of the ship’s vapour
manifold to a terminal liquid loading line, the vapour connection
ึ
should be clearly identified by painting the outboard 1 metre
section with yellow and red bands and by stencilling the word
‘VAPOUR’ in black letters upon it.

In addition, a cylindrical stud should be permanently attached to
each presentation flange face at the 12 o’clock position on the
flange bolt circle. The stud should project 25.4 mm (1 inch)
1
perpendicular to the flange face, and should be 12.7 mm ( ⁄2 inch)
in diameter, in order to prevent the connection of standard liquid
transfer hoses. Blank flanges, inboard ends of reducers and
hoses for the vapour line will have an extra hole to accommodate
the stud on the presentation flange (see Figure 11.3).

Full details of vapour manifold arrangements, materials and
fittings are contained in the OCIMF publication ‘Recommendations
งานห้อง Although all ‘closed’ cargo operations require in-tank pressures to
for Oil Tanker Manifolds and Associated Equipment’.

Vapour Over/Under-Pressure

be effectively monitored and controlled, the connection to a
vapour emission control system results in pressures within the
ship’s vapour spaces being directly influenced by any changes
that may occur within the terminal’s system. It is therefore
important to ensure that the individual cargo tank
pressure/vacuum protection devices are fully operational and that
loading rates do not exceed maximum allowable rates. In addition,
pressures within vapour collection piping systems should be
continuously monitored by sensors that incorporate high and low
pressure alarm functions connected to audible and visual alarms.

11.1.13.4 Cargo Tank Overfill
The risk of overfilling a cargo tank when using a VEC system is
no different from that when loading under normal closed

176 © ICS/OCIMF/IAPH 2006